Audio signal devices have been developed for the purpose of more independent hearing of an audio signal in an open environment or hearing aid. For example, an earphone may be connected with an electronic device wirelessly or wiredly to output an audio signal provided from the electronic device. In addition, a hearing aid is fitted in a user's ear so as to help a user hear an audio signal, for example, by amplifying the audio signal introduced into the user's ear.
A conventional audio signal device has a problem in that, since a user adjusts a volume level manually, it is difficult to hear an audio signal at a good volume level under a circumstance where the user cannot manually adjust the volume in a suitable manner. When the audio signal device is directed away from an ear, the volume of the audio signal may be merely reduced or may not be heard at all. However, in an environment where the audio signal device is in close contact with the ear inadvertently, there is a problem in that a hearing situation which is not desired by the user or which may cause physical damage to the user's hearing may occur.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.